Arc converter



Nov. 2 1926. 1,605,608

P.0.PEDERSEN ARC CONVERTER Original Filed June 21. 1919 1 vtlvroe w/ r/vcsszs P5052 a. P505285 Patented Nov. 2, 1926.

UNITED STATES PATENT OFFICE.

PEDER o. rnnnnsnn, or rnnnner rsenne, DENMARK, Assrenon T ro sen wran- LESS CORPORATION, A oonronn'rrolv or ARIZONA.

ARC CONVERTER.

Original application filed June 21, 1919, Serial No. 305,844, and in Denmark March 4, 1919. Patent No. 1,544,102, dated June 30, 1925. Divided and this application filed December 1, 1923.

This invention relates to an arc converter for producing high frequency oscillations in an electric circuit, and more particularly to the so called Poulsen arc.

The use of such arcs fed from a low frequency source to produce high frequency oscillations is now well-known; in such devices a magnetic blowout is provided for extinguishing the arc during each cycle of high frequency, the oscillations being produced by the rapid variations in arc length and resistance.

This application is a division of a prior application filed in my name, entitled Arc 1 5 generators, having Serial No. 305,844, and filed June 21, 1919, Patent No. 1,544,102, dated June 80, 1925.

It is one of the objects of my invention to increase the stability of an arc converter .0 of the Poulsen type.

In order to secure best results with an arc converter the magnetic field that influences the arc should be just strong enough to blow out the are once in each cycle. In case the magnetic field be materially weaker than this desired value, the arc will have a tendency to travel too far along the electrodes and away from the edges; this results in a reduced eliiciency owing to the existence of an unnecessarily high are voltage corresponding to this period, and furthermore the frequency of operation will also vary. But even with the most favorable value of the magnetic field to produce the desired extinction voltage, there is a gradual increase in arc resistance following the comparatively gradual rise of the extinction voltage, so that the efficiency of the arc is limited.

It is another object of my invention to overcome this effect as much as possible, by ensuring that there be little variation in resistance from the time of drawing to the time of extinction of the arc. Stating it in another way, the object is to reform the conditions of starting and blowing-out of the arc, whereby the arc resistance is reduced to a favorable minimum while the'arc is burning. According to the invention this is accomplished by providing the cathode with cooling or other means which limit-s the outward travel of the arc, and-regulates Serial No.

the temperature at the starting point for a desired high starting voltage. It is also pointed out in this application how the electrodes may be formed, or arranged, or formed and arranged, relatively to each other, to augment this increase in efiicicncy, by reducing to favorable values, the increase in length and resistance of the are during its period of burning in each cycle.

My invention possesses other advantageous features, some of which with the foregoing will be set forth at length in the fol lowing description, where I shall outline in full that form of the invention which I have selected for illustration in the drawings accompanying and forming part of the present specification. Although I have shown in the drawings but one embodiment of my invention, I do not desire to be limited thereto, since the invention as expressed in the claims may be embodied in other forms also.

Referring to the drawings:

Figure 1 shows for comparison the usual arrangement of the electrodes of an arc converter; and

Fig. 2 shows one embodiment of my invention.v

In the prior arrangements as illustrated in Fig. 1, the anode 1, which is shown as water cooled, is placed directly opposite a cathode 2. When the arc ignites it forms the path 3, and it is then gradually bowed out and increased in length until it is extinguished in the position 4. There is no limit placed on the travel of the arc, and itis possible that with a slightly inaccurate adjustment of the field, the arc may be extinguished only after it has been drawn out to an undesirable extent.

In the embodiment of my invention shown in Fig. 2, I arrange the anode 5 and cathode 6 in such a way that thearc must be drawn always in the position shown at 7, and must be extinguished always in the position shown at 8. In this way the arc length is kept within definite limits, and no undue resistance losses or other detrimental effects can occur. In the present instance to limit the travel of the arc, I provide blow pipes 9 and 10 near the cathode 6, which blow pipes direct acooling gas or liquid against the cathode 6. For example the blast may be hydrogen, coal-gas, alcohol, ether or the like. Several pipes, blowing from different directions may of course be employed. The pipes 9 and 10 may be adjusted in position relatively to each other and the cathode 6, in accordance with the requirements of the particular circuit that is connected to the are.

In order further to limit the increase in arc length between drawing and extinction, I prefer to offset the axes of the electrodes '5 and 6 so that they are out of alinement although substantially parallel. The active surface of anode 5 is bevelled as shown at 11 so as to form substantially an acute angle between it and the active surface of cathode 6. In this way there is a relatively small lengthening of the are between its starting and extinction positions.

I claim:

1. In an arc converter, an anode, a cathode, and one or more blow-pipes arranged for blowing a cooling blast against the cathode at an isolated point only, where the are is to be extinguished.

2. In an arc converter, an anode, a cathode the axis of which is out of alinement with that of the anode, one or more blowpipes for blowing a cooling blast against an isolated point only, of the cathode where the are has to be extinguished, and means for cooling the cathode at an isolated point only, where the are has to be drawn.

3. In an arc converter, a pair of electrodes between which an arc is to be drawn, said electrodes having substantially parallel, displaced axes, and extending in opposite directions.

' 4. In an arc converter, a pair of electrodes between which an arc is to be drawn, and one or more blow pipes arranged for blowing a cooling blast'against one of the electrodes at an isolated point only, where the arc is to be extinguished.

5. In an arc converter, a pair of electrodes between which an arc to be drawn, one or more blow pipes arranged for blowing a cooling blast against one of the electrodes at an isolated point only, where the arc is to be drawn, and one or more blow pipes for blowing a cooling blast against one of the electrodes at the isolated point only, where the are is to be extinguished.

t). In an arc converter, an anode, a cathode, one or more blow pipes arranged for blowing a cooling blast against the cathode at an isolated point only, where the arc is to be drawn, and one or more blow pipes for blowing a cooling blast against the cathoue at an isolated point only, where the arc is to be extinguished.

7. In an arc converter, a pair of electrodes between which an arc is to be drawn, the axes of said electrodes being displaced from each other and being substantially parallel. the electrodes extending in opposite directions so as to present limited adjacent active surfaces, the active surface of one of said electrodes being shaped so as to provide a relatively small increase in arc length as the are travels over this surface.

8. In an are converter, an anode, and a cathode, the axis of the anode being displaced and substantially parallel to that of the cathode, the electrodes extending in opposite directions so as to present limited adjacent active surfaces, and the active surface of the anode being so shaped as to pro vide a relatively small increase in arc length as the arctravels along this surface.

In testimony whereof, I have hereunto set my hand.

PEDER O. PEDERSEN. 

